Bicycle-seat-post clamp.



Patented Aug. 2|, |900.

J. B. L. MGKENZIE.

BICYCLE SEAT POST CLAMP.

(Apphcatxon filed Feb 6 1900 y (No Model.)

IDJCDLOP ma nunm's Farms nu., woramwo., msnmsmu. uA c UNITED STATES JOEL BAELow LAING MCKENZIE, or RAEWAY, NEW JERSEY.

,PATENT OEEICE.

BICYCLE-SEAT-POST CLAMP.

SPECIFICATION forming part 0f Letters Patent N0. 656,567, dated .August- 21, 1900. Application led February 6, 1900| Serial No. 4,252. (No model.)

To all whom t may concern,.-

Be'it known that I, JOEL BARLOW LAING MCKENZIE, acitizen of the United States, residing at Rahway, in the county of Union and State of New Jersey, have invented a new and useful Bicycle-Seat-Post Clamp, of which the following is a specification.

This invention relates to clamps for the seat-posts of bicycles, whereby the seat-post may be clamped'at different points of its ad j ustment to hold the seat at different elevations, the object of the invention being to provide a cheap and simple construction which will positively hold the seat-post in any position and in which, moreover, there will be no objectionable and unsightly protruding parts.

In the drawings forming a portion of this specification., and in which similar numerals of reference designate like and corresponding parts in the several views, Figure 1 is a View, partiallyin section and partially in elevation, showing the clamping mechanism carried by the seat-tube forging and gripping the seatpost shown in elevation. Fig. 2 is a detail perspective view of the follower shown in Fig. l, the position of the follower being reversed. Fig. 3 is a detail perspective view showing the split clamping-ring. Fig. 4 is a sectional view similar to Fig. 1, showing a modiication of the invention.

Referring now to the drawings, and more particularly to Figs. 1 and 3, 5 represents the seat-tube forging of a bicycle-frame andV to which are connected the seat-tube 6, the top bar 7, and the rear forksS in the usual manner. The lower end of the forging 5, which receives the seat-tube 6, has its internal diameter contracted to form a shoulder 9,`and within the upper enlarged portion of the forging is disposed a split clamping-ring 10, which rests upon the shoulder 9 and is held from rot-ation by means of a lug 12, which enters a recess 13 in the lower end of the ring. As shown in the drawings, the split ring 10 has a constant internal diameter, and its inner face is serrated or roughened to secure an eiicient grip upon the seat-post. In exterior shape the split ring is cylindrical at its upper portion and is frusto-conioal at its lower portion, and in this ring isv formed a cut whichgives it its split feature, the cut or split being spirally disposed from the upper edge of the cylindrical portion through the lower edge of the frustoconical portion and in the direction of rotation of the follower, hereinafter described, to compress the ring. In order to contract this split ring 10 upon the seat-post,v a follower 16a is disposed slidably within the forging 5, and this follower is in the form of a ring, the inner face of the lower end of which is beveled, as shown at 25, to bear against the tapered portion of the split ring 10, while at the opposite end of the follower is formed an inwardly directed flange 26, which fits snugly or is adapted to snugly receive the seat-post. A tubular nut 16, having exterior threads 17, is engaged with the threads 18 upon the inner face of the upper end of the forging 5 and is provided with perforations 27 to receive the lugs of a Spanner, through the medium of which the nuts may be screwed downwardly and into the forging and correspondingly move the follower upon the split ring to contract it. This operation will cause the split ring to engage the seat -post continuously, and thus firmly hold it with a minimum of pressure, which is not the case where the seatpost is engaged at separate points.

It will be noted that the split 18 of the ring is formed at the opposite side of the ring from the recess 13 in order that the engagement of the lug 12 with the recess will not interfere with the contraction and expansion of the ring. This ring is of spring material, so that when the follower is moved upwardly the ring will expand to release the seat-post and permit it to beadj usted.

In Fig. 4 of the drawings there is shown a construction which is the same in every respect as that shown in Fig. l, with the exception that in substitution of a separate follower and operating-nut these parts are formed integral.

It will be seen that in either of the constructions described the follower may be manipulated to cause the split ring to grip the seat-post continuously of the ring, so that all parts of the ring are closely engaged with the seat-post instead of engaging at intervals.

It will be understood that'the nut in each instance may have an angular head for engagement by a wrench and that other modiiications may be made in the manufacture of IOO the structure without departing from the spirit of the invention. t

What is claimed is- 1. In a seat-post clamp, the combination with a hollow block having an interior shoulder provided with a lug, of a split ring disposed upon the shoulder and having a recess with which the lug is engaged to hold the ring from rotation, the upper portion of the ring being cylindrical and the lower portion thereof frusto-conical and the ring having a serrated inner face, a follower within the block and adapted to' receive the frusto-conical portion of the ring to contract the latter, the split of the ring being disposed spirally from the upper edge thereof to the lower edge, and means engaged with the block for operating the follower.

2. In a seat-post cla-mp, the combination with a hollow block having an interior shoulder provided with a lug, of a split ring disposed upon the shoulder and having a recess with which the lu g is engaged to hold the ring from rotation, the upper portion vof the ring being cylindrical and the lower portion thereof frusto-eonical and the ring having aserrated inner face, and a follower movable in the block and adapted to receive and im pinge the frusto-eonieal portion of the ring to contract the latter, the split of the ring being spirally disposed from the upper edge thereof in the direction of rot-ation of the follower to compress the ring.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of two witnesses.

JOEL'BARLOW LAING MGKENZIE.

Witnesses:

R. S. HARRISON, H. M. BENNITT. 

